Raketa big zero, adjusting time issue

Hello there,

here is my thing with my vintage Raketa Big Zero.

I got the watch a couple weeks ago from my friend. The watch kept time pretty good, until recently. I play drums occasionally and I had Raketa with me, while I played (I just realized everything right after).

What happened, I believe, is the watch was subjected shock and since it's not a shock resistant, something happened, which resulted in gaining a 1 minute per hour.

This day is the third day of my observations. I found some instruction how to adjust it manually, but it looks it is still ahead.

The movement is: 2509HA

Could anyone advise what to do? And if it's a serious problem, how much it may cost to get it fixed.

thank you